|Publication number||US4260350 A|
|Application number||US 06/140,648|
|Publication date||Apr 7, 1981|
|Filing date||Apr 16, 1980|
|Priority date||Apr 16, 1980|
|Publication number||06140648, 140648, US 4260350 A, US 4260350A, US-A-4260350, US4260350 A, US4260350A|
|Inventors||Luther O. Russell, Jr.|
|Original Assignee||Fiber Industries, Inc.|
|Export Citation||BiBTeX, EndNote, RefMan|
|Patent Citations (11), Referenced by (6), Classifications (11), Legal Events (1)|
|External Links: USPTO, USPTO Assignment, Espacenet|
This is a continuation of application Ser. No. 920,611, filed June 29, 1978, now abandoned.
(i) Field of the Invention
The invention relates broadly to the filtration of fluids. More particularly, it relates to seals in replaceable packs for filtering highly pressurized high viscosity molten polymer and extruding the filtered polymer into shaped articles such as filaments and films.
(ii) Prior Art
Packs for filtering pressurized high viscosity polymeric material and forming the filtered liquid into spun filaments are well known in the art. A pack of relatively recent design and its mode of operation is disclosed in U.S. Pat. No. 3,307,216. Typically, all such packs are assembled from a mixture of re-useable components (such as housing, lid, spinnerette) and disposable components (such as inert granular material, gaskets, and screens for supporting the inert granular material). The average time interval between replacing packs has a significant effect on both the economics of the process and the quality of the product.
The invention arose out of the discovery that the type of pack disclosed in the forementioned U.S. Pat. No. 3,307,216 had certain drawbacks, particularly for the spinning of highly viscous material at high throughputs. In particular, it was found that some of the seals for controlling polymer flow were not consistently effective, resulting in both external polymer leaks out of the pack, and internal polymer leaks (or by-passing) within the pack. Both types of leak are highly undesirable.
It has now been found that the claimed invention, in which the rim of the screen supporting the inert granular material is swaged into the housing, significantly reduces the number of these highly undesirable leaks, and in addition halves the time to assembly the pack components into an integral unit. The improved seal design may be used with advantage in any replaceable filter of the type described regardless of whether the filter is integrally combined with an extrusion die. The improved seal designs are extremely valuable in melt spinning packs designed for use in combination with already constructed apparatus that imposes severe space limitations. The invention is surprising, particularly since the type of seal shown in U.S. Pat. No. 3,307,216 has been used commercially for over ten years in the manufacture of many billions of pounds of fiber.
FIG. 1 is a vertical cross section of an assembled melt spinning pack of the invention.
FIGS. 2, 3 AND 4 are horizontal fragmentary cross sections along lines 2--2, 3--3 and 4--4 respectively of FIG. 1.
FIG. 5 is a perspective view of an unassembled "top hat" screen and corresponds to item 6 of FIG. 1 in assembled form.
FIG. 6 is an enlarged view of Zone A of FIG. 1, as it looks during assembly of the pack prior to the swaging operation.
FIG. 7 is an enlarged view of Zone B of FIG. 1.
The Figures illustrate the preferred embodiments of the invention.
FIG. 1 is a vertical cross section of an assembled melt spinning pack incorporating the invention. In particular, FIG. 1 shows an improved replaceable pack for filtering pressurized high viscosity molten polymer and extruding the filtered polymer into shaped articles such as filaments and films, which pack comprises a housing (9) having an inlet port (19) and an outlet port (20), a lid (15) having an inlet port (11) and an exit port (21) and the lid being rigidly connected via a first gasket (7) to the housing around the lid's exit port and around the housing's inlet port, an extrusion die (2) rigidly connected via a second gasket (3) around the housing's outlet port, an internal lip (5) within the housing between the extrusion die and the inlet port of the housing, means for filtering the fluid immediately upstream of the lip, which filtering means comprises inert granular material (16) immediately upstream of a supporting rimmed fine mesh screen (6) whose annular rim contacts the housing's internal lip (5), wherein the improvement comprises: said screen's rim is swaged into said housing, whereby there is a reduced chance of some of said fluid and said granular material by-passing said screen. Likewise, FIG. 1 also illustrates an improved replaceable filtration unit for high viscosity fluids, which filter unit comprises a housing (9) having an inlet port (19) and an exit port (20), a rimmed fine mesh screen (6) between the ports for filtering the fluid, wherein the improvement comprises: said screen's rim is swaged into said housing.
FIG. 6 is an enlargement of Zone "A" prior to swaging of the rim of screen (6) into both the housing (9) and a grooved bridge plate (5). The screen is in the shape of a top hat and at least partly annular. It is preferred that the total radial interference fit imposed upon the rim of the screen be between 0.005 and 0.015 inches. Thus, in FIG. 6, the dimension A2 is greater than dimension A1, by an amount within the range of about 0.005 to 0.015 inches. Also, the dimension B2 is preferably greater than the dimension B1 by an amount up to 0.002 inches. It will, of course, be appreciated by one skilled in the art, that swaging of the unswaged rim of the screen as shown in FIG. 6 (and having the relative dimensions of A, A2, B1 and B2 as defined above) into the swaged rim as shown in FIG. 1, Zone A, must inherently result in the rim being outwardly swaged and toggle jointed into the housing. Webster's New Collegiate Dictionary (1961) defines toggle joint as "(a) device consisting of two bars jointed together end to end but not in line, so that when a force is applied to the knee tending to straighten the arrangement, the parts abutting . . . the ends of the bars will experience an endways pressure."
FIG. 7 is an enlargement of Zone B of FIG. 1, and shows the seal between the pack housing and lid. It shows a first gasket (7) in the form of a metal sleeve having a length, L, outer diameter, D, and wall thickness, T; and the housing's inlet port (19) has a square step around its inner face. The square step has a radial depth of about T and a height h. The value of h must be less than the value of L. It is preferred that the value of L/T be in the range 2 to 10, and most preferably in the range 4 to 7. It is preferred that T be in the range from 0.025 to 0.100 inches. The metal sleeve is preferably aluminum, copper, mild steel or stainless steel. It is preferred that the inside face of the lid has a counter bore of diameter D and depth d, and the value of the sum of h and d is equal to L in the assembled state and less than L in the unassembled state.
It is preferred that the third and remaining seal with the pack, the seal between the extrusion die (2) and the housing's outlet port (20) be obtained conventionally as shown in FIG. 1, which shows the housing (9) having a second lip around its exit port (20) that is rigidly connected to the extrusion die via a second gasket (3) by means of the pressure of the pressurized fluid within the pack.
while the foregoing, in combination with the drawings, illustrates the broadest and most preferred embodiments of the invention, it will of course be appreciated that other embodiments of the invention come within the scope of the broadest claims.
|Cited Patent||Filing date||Publication date||Applicant||Title|
|US2038348 *||Jan 28, 1935||Apr 21, 1936||Lyonnaise De Textiles Soc||Individual filter for the spinning of artificial filaments, threads, and the like|
|US2266368 *||Nov 10, 1938||Dec 16, 1941||Du Pont||Apparatus for the production of artificial structures|
|US2607954 *||Jun 17, 1950||Aug 26, 1952||Celanese Corp||Method and apparatus for forming gel-free thermoplastic films|
|US2732585 *||Feb 12, 1952||Jan 31, 1956||Spinner head|
|US3307216 *||Oct 5, 1964||Mar 7, 1967||Fiber Industries Inc||Annular spinning apparatus|
|US3469279 *||Oct 15, 1964||Sep 30, 1969||British Nylon Spinners Ltd||Spinneret for heterofilaments|
|US3475527 *||Dec 11, 1967||Oct 28, 1969||Monsanto Co||Process for destroying melt crystalline order in fiber-forming polymers|
|US3724064 *||May 3, 1972||Apr 3, 1973||Mott Metallurg Corp||Sealing method|
|US3771664 *||Jul 5, 1972||Nov 13, 1973||Dover Corp||Filter seal|
|US3797982 *||May 8, 1972||Mar 19, 1974||Colgate Palmolive Co||Extruder output multiplier|
|JPS538811A *||Title not available|
|Citing Patent||Filing date||Publication date||Applicant||Title|
|US5217659 *||Dec 17, 1991||Jun 8, 1993||Wellman, Inc.||Repair of filtration elements for polymer manufacture|
|US5246589 *||Jan 12, 1993||Sep 21, 1993||Wellman, Inc.||Repaired filtration elements for polymer manufacture|
|US5387097 *||Dec 7, 1992||Feb 7, 1995||Akzo Nv||Self-sealing spin pack|
|US6171536 *||Apr 10, 1998||Jan 9, 2001||Arteva North America S.A.R.L.||Apparatus and method for melt spinning of molten polymeric material|
|US7520137 *||Jun 2, 2005||Apr 21, 2009||Alstom Technology Ltd||Method of controlling the injection of liquid into an inflow duct of a prime mover or driven machine|
|US20050279101 *||Jun 2, 2005||Dec 22, 2005||Juergen Hoffmann||Method of controlling the injection of liquid into an inflow duct of a prime mover or driven machine|
|U.S. Classification||425/197, 425/198, 264/176.1|
|International Classification||B01D29/00, D01D1/10|
|Cooperative Classification||B01D29/0036, D01D1/106, B01D29/0027|
|European Classification||B01D29/00A8, D01D1/10D, B01D29/00A10K14|
|Mar 19, 1984||AS||Assignment|
Owner name: CELANESE CORPORATION A DE CORP
Free format text: ASSIGNMENT OF ASSIGNORS INTEREST.;ASSIGNOR:FIBER INDUSTRIES INC;REEL/FRAME:004239/0763
Effective date: 19841230